Add Lua function to get a player's role (#366)

Adds `MP.GetPlayerRole(player_id)` to the Lua API to get a player's role
("USER", "EA", "MDEV", "STAFF", "ET") by their player id.
Currently you can only get someone's role in onPlayerAuth from the
parameters and in onVehicleSpawned and onVehicleEdited from the packet
data, but not in onPlayerJoin for example without storing it.

include/TLuaEngine.h

@@ -263,6 +263,7 @@ class TLuaEngine : public std::enable_shared_from_this<TLuaEngine>, IThreaded {
         sol::table Lua_TriggerGlobalEvent(const std::string& EventName, sol::variadic_args EventArgs);
         sol::table Lua_TriggerLocalEvent(const std::string& EventName, sol::variadic_args EventArgs);
         sol::table Lua_GetPlayerIdentifiers(int ID);
+        std::variant<std::string, sol::nil_t> Lua_GetPlayerRole(int ID);
         sol::table Lua_GetPlayers();
         std::string Lua_GetPlayerName(int ID);
         sol::table Lua_GetPlayerVehicles(int ID);

src/TLuaEngine.cpp

@@ -595,6 +595,16 @@ sol::table TLuaEngine::StateThreadData::Lua_GetPlayerIdentifiers(int ID) {
     }
 }
 
+std::variant<std::string, sol::nil_t> TLuaEngine::StateThreadData::Lua_GetPlayerRole(int ID) {
+    auto MaybeClient = GetClient(mEngine->Server(), ID);
+    if (MaybeClient) {
+        return MaybeClient.value().lock()->GetRoles();
+    } else {
+        return sol::nil;
+    }
+}
+
+
 sol::table TLuaEngine::StateThreadData::Lua_GetPlayers() {
     sol::table Result = mStateView.create_table();
     mEngine->Server().ForEachClient([&](std::weak_ptr<TClient> Client) -> bool {
@@ -892,6 +902,9 @@ TLuaEngine::StateThreadData::StateThreadData(const std::string& Name, TLuaStateI
     MPTable.set_function("GetPlayerIdentifiers", [&](int ID) -> sol::table {
         return Lua_GetPlayerIdentifiers(ID);
     });
+    MPTable.set_function("GetPlayerRole", [&](int ID) -> std::variant<std::string, sol::nil_t> {
+        return Lua_GetPlayerRole(ID);
+    });
     MPTable.set_function("Sleep", &LuaAPI::MP::Sleep);
     //  const std::string& EventName, size_t IntervalMS, int strategy
     MPTable.set_function("CreateEventTimer", [&](sol::variadic_args Args) {